Pack Size: 20, 100, 300
Year: 2026
Accepted Scientific Name: Echinocereus rigidissimus subsp. rubispinus (Gerhart Frank & A.B.Lau) N.P.Taylor
Synonym: Echinocereus pectinatus var. rubrispinus Gerhart Frank & A.B.Lau
Origin and Habitat:
Echinocereus pectinatus var. rubrispinus is a distinctive cactus native to northern Mexico, particularly the Sierra Oscura region of western Chihuahua. It inhabits arid mountain slopes, rocky hillsides, and dry shrublands, growing in mineral-rich soils with excellent drainage. Unlike many Mexican cacti associated with limestone habitats, this subspecies prefers soils low in calcium carbonate, often with slightly acidic conditions. Its natural environment experiences strong sunlight, warm summers, cool winters, and seasonal rainfall followed by extended dry periods. Plants grow among rocks, grasses, and sparse desert vegetation, where they are adapted to limited moisture and considerable temperature fluctuations. The subspecies is especially valued for its colourful spination and spectacular flowers.
Description:
Echinocereus pectinatus var. rubrispinus, commonly known as the Ruby Rainbow Cactus, is a slow-growing cactus characterized by its compact, cylindrical shape and distinctive bands of colourful spines. Mature stems typically reach approximately 4–10" tall and 2–3" in diameter, remaining solitary or occasionally forming small clusters with age. The dark green body develops numerous narrow ribs densely covered with short, comb-like radial spines arranged closely against the stem. These spines display striking ruby-red, pink, violet, and pale cream tones, creating attractive horizontal bands around the plant. Unlike many other Echinocereus species, prominent central spines are generally absent. Mature plants produce spectacular, funnel-shaped flowers approximately 3–4" across, displaying vivid magenta-pink to reddish-purple petals with contrasting pale throats and prominent stamens. Flowers emerge near the upper portion of the stems during spring and early summer, followed by rounded, spiny fruits. Its colourful spination and exceptionally large flowers make it a highly desirable addition to specialist cactus collections.
Cultivation:
Zone: 9–11; protect from prolonged frost and excessive winter moisture.
Temperature: Optimal growth at 18–30 °C. Maintain winter temperatures around 5–10 °C under dry conditions.
Growth Rate: Slow, gradually developing compact, cylindrical stems with increasingly colourful bands of dense spines.
Soil: A highly mineral, fast-draining cactus mixture containing pumice, fine gravel, crushed granite, and a small proportion of organic matter. A slightly acidic to neutral growing medium is preferred; avoid excessive limestone.
Watering: Water thoroughly during active growth, allowing the growing medium to dry completely between waterings. Reduce watering significantly during autumn and keep dry during winter dormancy.
Fertilizing: Apply a diluted, low-nitrogen cactus fertilizer every 2–3 weeks during active growth. Discontinue feeding during winter.
Light: Bright light to full sun. Strong light encourages compact growth and vibrant ruby-red spination. Provide protection from intense afternoon sunlight during extreme heat, particularly for young plants.
Pests and Diseases: Susceptible to mealybugs, root mealybugs, spider mites, and root rot associated with excessive moisture or poorly draining growing media.
Germination Info:
Temperature: 27 °C.
Surface Sown: Yes. Sow seeds on the surface of a fine, sterilized cactus growing medium and press lightly into place. A very thin covering of fine mineral material may be used.
Germination Time: Approximately 7–28 days under favourable conditions, although some seeds may require longer.
Moisture: Maintain consistent surface moisture and high humidity during germination, avoiding waterlogged conditions.
Light: Bright, indirect light. Avoid direct sunlight on covered seed trays.
After Germination: Gradually increase ventilation as seedlings establish. Maintain moderate moisture until young plants develop stronger root systems and begin producing characteristic comb-like spines.
